Touch screen
A typical PDA, at this time, offers touch screen for data entering, but there is more to this little wonder than meets the eye. They also have a memory card slot for the storage of data alone with one or more of the following: a directional pad and either the numeric keypad or a thumb keyboard for input using softkeys, IrDA, Bluetooth and/or WiFi. However, many PDAs (typically those used primarily as telephones) may not have a touch screen. Having only a few buttons which are usually reserved for shortcuts to often used programs, most of the original PDAs, such as the Apple Newton and Palm Pilot, featured touchscreen for user interaction. Including Window Mobile devices, PDAs with touch screens, will often have a detachable stylus. This interaction using the stylus is done by tapping on the screen to make menu choices and to activate buttons. Highlighting can also be done by dragging the stylus and text can be done in four different ways. The virtual keyboard is one way, the chorded keyboard or external keyboard that is connected by Bluetooth, IR or USB is another. Letter or word recognition can also be used where the touch screen is used to write letters or words and stroke recognition. Graffiti is a Palm implementation where predefined set of strokes will represent a number of characters used in input.
